MULLARD GZ34 CV1377 MATCHED PAIR OF 4 NOTCH F31 NOS BRITISH VINTAGE NEW OLD STOCK NEW IN BOX VALVES TUBES 

BRITISH VINTAGE MULLARD RECTIFIER VALVES WITH A WONDERFUL CLEAR WARM SOUND = F31 TYPES

MADE IN THE MULLARD BLACKBURN FACTORY IN GREAT BRITAIN 

MULLARD BLACKBURN " B " FACTORY F31 CODES ETCHED INTO THE GLASS OF THE BOTH OF THE VALVES

MADE IN GREAT BRITAIN IN AUGUST OF 1961 

BIG BROWN BASE WITH CLEAN SHINY UNUSED METAL PINS

ORIGINAL VINTAGE MULLARD BOXES WITH VINTAGE BROWN TISSUE AND CARDBOARD WRAPPING

THESE TUBES TESTED AT 100% STRONG NOS READINGS ON MY B&K 747 + HICKOK TV-7 TUBE TESTERS

TESTED FOR  GAS AND  SHORTS

FREE PAY PAL FEES

FREE INTERNATIONAL AIRMAIL SHIPPING - EXCEPT TO RUSSIA 

CUSTOMS FRIENDLY DECLARATION AVAILABLE TO ALL BUYERS

PLEASE SEE MY EXCELLENT E BAY CUSTOMER FEEDBACK AFTER OVER 15 YEARS OF SELLING VINTAGE VALVES ON EBAY.

PLEASE SEE MY EBAY 15 YEAR SELLING AWARD IN THE PHOTOS

Up for sale is an incredibly rare, investment-grade NOS NIB (New Old Stock, New in Box) matched pair of Mullard CV1377 full-wave retifier tubes. These are the legendary CV1377 military-spec equivalents to the iconic Mullard GZ34 / 5AR4. These valves come in their original Mullard boxes.
Both tubes feature the highly coveted f31 date codes etched into the glass, proving genuine manufacture at the world-famous Blackburn, UK plant.
This is a true "Same-Code" pair, meaning they were produced in the same factory batch. They feature the heavy big brown bases, robust copper 4 notch sawtooth plates, and classic O-getters that define the golden era of British tube manufacturing.
Product Details:
  • Brand / Origin: Mullard (Blackburn, Great Britain)
  • Tube Type: CV1377 (Premium Military GZ34 / 5AR4 / 5U4G substitute)
  • Base: Fat / Big Brown Base
  • Etched Codes: f31 (Blackburn)
  • Internal Structure: 4 NOTCH Dual copper sawtooth plates, O-getter
  • Condition: Pristine NOS (New Old Stock) in original Mullard boxes
Performance & Sound:
The Mullard f31 brown base is widely regarded by audiophiles and guitarists as one of the finest rectifiers ever made. It delivers a rich, liquid, and deeply dynamic tone with unparalleled reliability. Perfect for upgrading high-end hi-fi amplifiers or classic vintage guitar amps (like Marshall, Vox, or Fender).

They have been tested on  my B& K747 tube tester at 100% strong tubes with no sign of gas or shorts